Moulds for forming footwear

ABSTRACT

A mould assembly for for forming footwear with molded soles, e.g. by injection moulding, in which movable welt plates are mounted adjacent the sole mould, e.g. on pivots or on a parallelmotion linkage on the mould itself, and are movable between a closed position in which they define the welt surface and an open position in which they permit the moulded sole to be withdrawn from the mould. They are arranged to be automatically returned to the closed position before the commencement of each moulding operation. The automatic return to the closed position may be effected by gravity, with or without the assistance of springs or bobweights, or by cam means associated with a moving last assembly. The opening movement may be effected simply by the withdrawal of the last from the mould. A unitary mould may be used, with the welt plates mounted on light supporting blocks pivotally mounted outside the side wall of the mould.

United States Patent Christie et al.

[ 1 MOULDS FOR FORMING FOOTWEAR [72] Inventors: Gerald Anthony Chrlstle, Bath; Brian Reginald Doble, Keynsham; Alec Roy Bromfleld, Kingswood, all of England [73] Assignee: G. B. Britten 8: Sons Limited, Bristol, En-

gland [22] Filed: May 5, I970 211 Appl. No.: 34,760

[30] Foreign Application Priority Data Nov. 5, 1969 Great Britain ..54,l 19/69 [52] U.S. Cl ..425/1 19, 425/441 [5 1] Int. Cl ..B29c 1/00 [58] FleldotSeu-eh ..18/17S,34S,42H

[ 56] References Clted UNITED STATES PATENTS 3.523333 8/1970 Taylor et H 3,172,157 3/1965 Rollman et al.... ..18/17 S 3,102,286 9/1963 Minick 18/17 S UX 3,358,333 12/1967 Kitchener et al.. 18/17 S X 3,314,640 4/1967 Snow ....18/42 H X 3,403,423 10/1968 McMorrow et a]. 18/42 H [45] July 18, 1972 FOREIGN PATENTS OR APPLICATIONS 1,052,861 3/1959 Germany ..l8/34S 1,264,686 5/1961 France ..l8/34S Primary Examiner-J. Howard Flint, Jr. Atl0meyHall, Pollock and Vande Sande ABSTRACT A mould assembly for for forming footwear with molded soles, e.g. by injection moulding, in which movable welt plates are mounted adjacent the sole mould, e.g. on pivots or on a parallel-motion linkage on the mould itself, and are movable between a closed position in which they define the welt surface and an open position in which they permit the moulded sole to be withdrawn from the mould. They are arranged to be automatically returned to the closed position before the commencement of each moulding operation. The automatic return to the closed position may be effected by gravity, with or without the assistance of springs or bobweights, or by cam means associated with a moving last assembly. The opening movement may be effected simply by the withdrawal of the last from the mould. A unitary mould may be used, with the welt plates mounted on light supporting blocks pivotally mounted outside the side wall of the mould.

8 Claims, 11 Drawing figures Patented July 18, 1972 5 Sheets-Sheet 1 F IG.

Climbie 0n VENT ATTORNEYS Patented July 18, 1972 3,677,679

5 Sheets-Sheet I5 I V 6 @Y@ @1 4 T I I 52 \56 so --a 58 56 52 W PM mm ATTORNEY Patented July 18, 1972 3,677,679

5 Sheets-Sheet 4 I 60 4656 is 45 71 4149 5'1 45 51 57 WqM/M/ ATTORNEY Patented July 18, 1972 5 Sheets-Sheet 7,

M TURNEY MOULDS ron FORMING roorwaxn CROSS REFERENCE TO RELATED APPLICATION The present application is related to Christie et al. US. application Ser. No. 34,761 filed May 5, 1970, for Molding Machine With Pivoted Welt Plates".

BACKGROUND OF THE INVENTION This invention relates to mould assemblies as used for forming footwear with moulded soles. The invention is particularly applicable to moulds designed for injection moulding processes.

In some typical moulding machines for forming moulded soles, the preformed upper is placed on a moulding last and the last is introduced into the working position of a moulding machine which is provided with three other separately movable mould parts arranged to define with the shoe upper the sole cavity. One of these three mould parts is a sole mould vertically opposed to the last and movable vertically by means of a pneumatic ram. In addition there are two separate laterally movable side moulds, each controlled by a separate pneumatic ram. The side moulds may be mounted on heavy swinging plates pivotally attached to the main frame of the machine on a vertical axis. Each side mould is accurately profiled to form the side surfaces of the sole moulding cavity and to make close sealing engagement with the adjacent side surfaces of the sole mould. Along the inner edge of each side mould remote from the sole mould there is fixed a welt plate, usually of steel, arranged to extend inwards into close contact with the adjacent parts of the shoe upper when the upper is in the correct position for moulding of the sole. These welt plates define the welt surfaces of the sole and are commonly transversely grooved to give the appearance of stitching on the moulded welt.

In the normal operation of such a moulding machine, after the molding last with the shoe upper in position has been located at the moulding station, an automatic control cycle first causes the sole mould to move vertically to a position spaced from the last, and the two side moulds are then moved inwards into close engagement with the sole mould and with the welt plates closely adjacent to the upper on the last, and finally the last itself is moved a short distance vertically to make effective sealing engagement with the welt plates. After the injection process the two side moulds are moved apart to allow the completed shoe, with the sole moulded thereon, to be removed.

SUMMARY OF THE INVENTION The present invention from one aspect consists broadly in a mould assembly for forming footwear with moulded soles comprising a sole mould member defining a cavity having walls corresponding to the bottom and sides of a sole, and a plurality of movable welt plates mounted adjacent said sole mould member, said welt plates being movable between a closed position in which they define the welt surface of the sole and an open position in which they permit the moulded sole to be withdrawn from the mould, and said welt plates being arranged to be automatically returned towards the closed position before the commencement of each moulding operation.

In forming a moulded sole, where the sole mould cavity is closed by the shoe upper in position on a last above the mould, the upper surface of the mould must conform to the general shape of the last and is necessarily not flat. The surface of a movable welt plate designed to engage the upper surface of the mould is likewise not flat, and must conform to the shape of the upper mould surface. Difiiculties can be encountered in making a welt plate of the desired shape economically and accurately.

Accordingly from another aspect this invention consists in a mould assembly for forming footwear with moulded soles, comprising a sole mould member having a base surface and an upstanding wall extending around the periphery of said base surface and substantially perpendicular thereto to define base and side walls of a mould cavity, movable support members disposed adjacent the outside of said upstanding wall, each support member having a top surface which in one position of said support member lies flush with the top surface of the ad jacent portion of said upstanding wall, and welt plates attached to said top surfaces of said support members, whereby said welt plates are movable between a closed position in which they overlie the top of said upstanding wall and define the welt surface of the sole and an open position in which they permit the moulded sole to be removed from the mould, said welt plates being arranged to be automatically returned to the closed position before the commencement of each moulding operation.

Preferably each welt plate is pivotally attached to the sole mould member, and according to a preferred feature of the invention each welt plate or supporting member is pivotally mounted on an axis which is spaced laterally from the vertical side wall of the sole mould member and also lies below the level of the respective welt plate to ensure that the edge of the welt plate does not move inwards towards the upper of the shoe at the start of the pivotal movement of the plate. Alternatively the welt plates may be carried by parallel guides or linkages so as to move linearly, or with parallel motion, in directions inclined outwards away from each other. This arrangement is particularly useful where side sealing as opposed to top sealing of the mould cavity is required, ie where the final closing of the cavity must be effected from the sides after the last has been lowered to its final position.

Each welt plate is automatically returned fully or partly towards its closed position after a moulded sole has been withdrawn. For example each welt plate may be returned by a spring or gravity operated device. The welt plates may alternatively be actuated in synchronism with the last, for example through cam mechanisms.

The invention also consists in a moulding machine for forming footwear with moulded soles including a mould assembly as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS The invention may be performed in various ways and several specific embodiments will now be described by way of example with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a front view ofa moulding machine incorporating a mould assembly according to the invention,

FIG. 2 is a plan view ofthe mould assembly of FIG. 1,

FIG. 3 is two half-sections through the mould assembly, the left half being on the line 343 3g and the right half being on the line 3b 3 b of FIG. I,

FIG. 4 is two further half-sections through the mould assembly, the left half being on the line 4Q 4g and the right half being on the line 4b- 4b of FIG. 1,

FIG. 5 is an elevation of a welt plate of a modified arrangement with an attached bob weight,

FIG. 6 is a side elevation of a moulding last in operative position above a mould assembly according to another embodiment of the invention,

FIG. 7 is a front elevation, i.e. a view from the left of FIG. 6,

FIG. 8 is a section on the line 8-8 of FIG. 6, but to a larger scale,

FIG. 9 is a detail sectional view similar to FIG. 8 but to a larger scale and showing some modifications,

FIG. I0 is a plan view of the sole mould assembly, and

FIG. I I is a view similar to FIG. 7 of a further embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the sole moulding machine shown in FIG. I, a last assembly generally indicated at L comprises a pair of lasts 1, l detachably secured by clamps 2 on respective parallel lastsupporting plates 3 welded to a tubular shaft 4 rotatably mounted at its ends in trunnions 5,5 carried by respective vertical columns 6,6. The columns 6,6 carrying the last assembly L can slide vertically in guides 7,7 and are connected at their lower ends by a cross-member 8 to the middle of which is attached the upper end of a vertically acting, automatically con trolled, pneumatic ram 9.

Rotation of the tubular shaft 4 will bring the lasts 1,! in turn into the operative position relative to a sole mould assembly generally indicated at S and shown in more detail in FIGS. 2 to 5. Operation of the ram 9 moves the last assembly L vertically, to lower it into contact with the sole mould assembly S for moulding and to raise it therefrom afier moulding. An injection mechanism of known type, generally indicated at l, is provided beneath the sole mould assembly S and connected thereto, for supplying the mould with controlled amounts of a plastic sole moulding material, such as polyvinylchloride, in the liquid state.

In the example of FIGS. 1 to 5, the sole mould assembly S comprises a sole mould member made up of two side mould units I0, 11, formed separately, and a bottom mould unit 30 having an upper surface corresponding to the desired shape of the lower surface of the sole and rigidly secured between the side mould units 10, II. The bottom mould unit 30 has a periphery corresponding to the inner peripheries of the side mould units I0, 11. The side mould units could be formed integral with one another as one rigid block, though for manufacturing purposes the two side mould units may be machined separately and subsequently rigidly secured together as shown. The bottom mould unit 30 could be formed integral with one or both side mould units 10, II. The side mould units are immovably mounted and in themselves are of generally conventional construction, having inner surfaces which define the side walls l2, l3 ofa mould cavity I4 having the shape ofa particular footwear sole. On the top surface 32 of each side mould unit [0, I! there is respectively provided a pivoted welt plate l5, 16, each of which in plan has an inner edge 17 of generally the same profile as the respective side mould unit I0, II but which projects inwards therefrom a distance of ap proximately one-quarter inch, the lower surface 18 of this projecting part of the welt plate being grooved or corrugated (not shown) to produce the usual stitching effect on the welt surface of the sole. Each welt plate 15, l6 has an upstanding longitudinal side rib 25 through which it is pivotally attached to the respective side mould unit 10, II on a horizontal longitu dinal pivot axis I9, 20, respectively, which is spaced laterally away from the moulding cavity 14 and also displaced vertically below the welt surface 18 of the welt plate. Hinge portions 28 are fixed to the adjacent side mould unit 10, 1] and hinge portions 28g are fixed to the upstanding rib 25 on the adjacent welt plate, [5, I6 while a hinge pin 27 passes through both portions 28 and 28g. Spacers 29 are provided between the hinge portions 28 and 2813. As can be seen by comparing FIGS. 3 and 4, the height of the welt plates l5, l6 and of the side mould units 10, l I, varies along the length of the cavity.

In the operation of forming a moulded sole with such a mould assembly, an upper is placed on a moulding last 1 and brought into the operative position above the mould assembly and is then lowered by means of the automatically controlled pneumatic ram 9 until the edge surfaces of the shoe upper are in sealing engagement with the inner lips I7 of the welt plates l5, 16. In this position the proper mould cavity dimensions are obtained and a selected plastics material is then injected into the cavity from below through an aperture 24 in the bottom mould unit 30, by means of the injection mechanism I. To withdraw the completed shoe from the mould it is merely necessary to raise the last 1 and in this withdrawal movement the pivoted welt plates 15, 16 swing upwards about their hinge axes 19, 20, and are thereby simultaneously withdrawn laterally out of the path of the welt of the sole, due to the positioning of the axes 19, 20 below the welt surface [8. When the shoe has been fully withdrawn the welt plates 15, I6 will be in an inclined position and will return automatically to their closed positions under their own weight. If desired they could be spring biased towards their closed positions, e.g. by a coil spring replacing one or more of the hinge portions 28, 28g, and stressed in torsion with one end engaging the rib 25 and the other end engaging the side of the sole mould member Ill.

The moulding machine could be designed so that the sole could be moulded with the assembly inverted from the position shown in FIGS. 3 and 4. A welt plate 23 for such an arrangement is shown in FIG. 5. An arm 21 secured to the hinge portion 28 of the welt plate 23 projects on the far side of the pivot axis I9 and is attached to a steel bob weight 22 arranged to tend to cause the welt plate 23 to move automatically into the horizontal attitude shown in FIG. 5. The welt plate 23 may be of aluminum and attached to a steel hinge portion 28 so that in conjunction with the weight 22 it has a center of gravity at 26. If the bob weight 22 only partly returns the welt plate 23 to a horizontal position, it may readily be fully closed by hand. In addition or as an alternative to the bob weight 22, a spring may be fitted to ensure that the welt plate closes fully.

In the embodiment of FIG. 5 the shoe upper is placed on the moulding last in an inverted position below the mould assembly and is then raised into the moulding position. To withdraw the completed shoe, the last is lowered (or the mould assembly is raised).

It may be desirable in some circumstances to provide additional sealing means between the welt plates 15, I6 and the upper surfaces 32 ofthe side mould units II], II to prevent the injected material entering between these two parts. In some cases it may also be desirable to form the welt plates I5, 16 in a number of separate components each individually movable, and some of these component welt plates may be pivotally mounted on hinge axes which are inclined relative to one another, thus facilitating withdrawal of the well plates adjacent the toe and heel of the moulded footwear.

In the example shown in FIGS. 6 to 9 of the drawings, a sole mould assembly comprises a sole mould member 40 (FIGS. 7, 8) made for example of aluminum. The sole mould member 40 is formed as one integral rigid block with an integral upstanding continuous wall 41 (FIG. 8) machined so as to have a continuous, uninterrupted, inner surface 42 which defines the side wall of a mould cavity 43 having the shape of a particular footwear sole. The bottom of the cavity 43 is defined by a base surface or wall 47, shaped to give the required form to the sole and heel of the moulded sole.

Two pivotally mounted supporting members 44, 45 (FIGS. 6 and 8) are respectively disposed on opposite sides of the sole mould member 40. The undersurfaces of the supporting members 44, 45 are flat and normally rest, as shown, on the fiat horizontal upper surface 46, (see FIGS. 8 and 9) of the sole mould member 40 outside the wall 41. In this position, inner surfaces 48, 49 of the supporting members 44, 45 are in close engagement with the outer surfaces of opposite portions of the wall 41, but they could be spaced therefrom.

At each end, the supporting members 44, 45 have fiat plates 50, 51 secured to their vertical end surfaces. Lateral exten sions 52, 53 on the ends of the plates 50, 51 receive plain shouldered portions of screws 54, 55 which are secured in blocks 56, 57 screwed to opposite vertical sides of the sole mould member 40. The screws 54, 55 at opposite ends of each side of the sole mould member 40 are aligned on common horizontal axes 58, 59, and thus form the hinge pivots for the supporting members 44, 45. Alternatively, a hinge system as shown in FIG. 2 could be used. Each of the supporting members 44, 45, is preferably formed in a light alloy, and is arranged to engage against the inside of the upper portion of a respective reinforcing steel bar 60, 61 attached to the vertical side of the base member 40 and projecting a short distance above it, so as to locate the member 44, 45 accurately when in the position shown and to resist lateral stresses, even if the hinges 54, 55 become worn. The lower edges of the end plates 50, 51 extend below the bottoms of the supporting members 44, 45 and engage against the vertical end surfaces of the sole mould member 40, as best seen in FIG. 9, to locate the members 44, 45 longitudinally.

The wall 41 has an upper or top surface 62 which is curved in profile, as seen in side elevation, to correspond to a desired welt surface on the moulded sole. The upper surfaces 64, 65 of the supporting members 44, 45 are similarly curved, as seen in FIG. 6, to lie flush with the surface 62. Conveniently the supporting members 44, 45 are held on the surface 46 of the sole mould member 40 and their upper surfaces 64, 65 are then machined to be flush with the surface 62. The base surface 47 of the mould cavity is above the surface 46 on the mould member 40 outside the wall 4], but it could be partly or wholly the level of the surface 46.

After the upper surfaces 64, 65 of the supporting members 44, 45 have been machined as described, relatively thin steel welt plates 66, 67 are secured thereto by screws 68 extending through holes in the welt plates 66, 67 and drilled and tapped holes in the respective supporting member 44, 45.

With this arrangement, the welt plates are relatively easily, and accurately, made to conform to the desired shape. Each welt plate has a chamfered inner edge 69, which has in plan generally the same profile as the adjacent part of the inner surface 42 of the wall 41 but which projects inwards therefrom a distance of approximately one-quarter inch, the lower surface 70 (see FIG. 8) of this projecting part of the welt plate being grooved or corrugated (not shown) to produce the usual stitching effect on the welt surface of the sole, if desired. The hinge axes 58, 59 are displaced vertically below the welt surfaces 70 of the welt plates 66, 67. As best shown in FIG. 6, the height of the welt plates 66, 67, and of the supporting members 44, 45, varies along the length of the mould cavity 43.

lf desired a shim 100 (FIG. 9) may be used between a welt plate 66, 67, and the respective supporting member 44, 45 and the inner edge 101 of the shim may project inwardly of the inner surface 42 of the wall 41. The shim may extend along only part of the side of the mould cavity 43. FIG. 9 also shows diagrammatically a coil spring [02 which may be disposed about the hinge axis 58 and stressed in torsion with one end 103 contacting the supporting member 44 and the other end 104 contacting the rail 60, so as to assist the return of the member 44 and welt plate 66 to the closed position shown.

ln the operation of forming a moulded sole with such a mould assembly, a shoe upper which may be attached to an insole, or merely stitched to a piece of fabric as in so-called "bag lasting or slip lasting is placed on a moulding last 1, above the mould assembly, and is then lowered, preferably by an automatically controlled hydraulic ram as indicated at 9 in FIG. 1, or by a toggle mechanism, until the edge surfaces of the shoe upper are in sealing engagement with the inner, chamfered, edge 69 of the welt plates 66, 67. In this position the proper mould cavity dimensions are obtained and the selected plastics material is then injected into the cavity from below through a vertical bore 71 (see FIGS. 8 and 10) in the sole mould member 40. To withdraw the completed shoe from the mould it is merely necessary to raise the last (or to lower the mould assembly) and in this withdrawal movement the pivoted supporting members and welt plates will swing upwards about their hinge axes and simultaneously withdraw laterally out of the path of the welt of the sole. When the shoe has been fully withdrawn the welt plates 66, 67 will be in an inclined position and will return automatically to their closed positions under their own weight, or with the assistance of springs 102, iffitted.

The sole could be moulded with the assembly inverted from the position shown in the drawings. in such an arrangement a part of the supporting member 44, 45 may project laterally beyond the pivot axis 58, 59 and be attached to a steel bob weight or a spring (not shown) arranged to tend to cause the supporting member and welt plate to move automatically into a horizontal attitude, in the manner described with reference to FIG. 5. In this case the shoe upper is placed on the moulding last in an inverted position below the mould assembly and is then raised into the moulding position. To withdraw the completed shoe, the last is lowered (or the mould assembly is raised).

It may be desirable in some circumstances to form the supporting members 44, 45 and welt plates 66, 67 in a number of separate components each individually movable, and some of these components may be pivotally mounted on hinge axes which are inclined relative to one another, thus facilitating withdrawal of the welt plates adjacent the toe and heel of the moulded footwear.

It will be appreciated that as the side wall of the mould cavi ty 43 is defined by the continuous inner surface 42 of the wall 41, the side surface of the moulded sole will have no mould marking or flash but will be smooth. It would, however, be possible to make the sole mould member 40 from two side mould members, each having a wall upstanding from a base and having hinged thereto a supporting member carrying a welt plate, the two side mould members being rigidly secured together so that the inner surfaces of the walls define the side of the mould cavity.

In a moulding machine having a mould assembly in accordance with any of the above described embodiments of the invention, the guides which are normally required in conventional machines for carrying movable side moulds can be omitted, together with the operating rams for the side moulds, and the associated control mechanism. This results in very considerable simplification and greatly reduces the cost of manufacture of the machine. The welt plates can be returned simply by gravity (with or without bob weights) or by springs or may be directly actuated by the last assembly itself, or its actuating mechanism, as described below, and require no special automatic control gear.

The embodiments described above are essentially based on "top sealing" methods, in which the lasted shoe upper is pressed down on to the upper edges of the welt plates to form a complete sole mould cavity. ln some applications top sealing is undesirable or impracticable: this may apply for example where the shoes have "mudguards or high foxing, i.e. where the moulded sole is continued upwards around the flanks of the shoe upper. In such cases it is necessary that the welt plates should not close against the shoe upper until after it has been moved vertically into the correct position in relation to the sole mould member, and the welt plates must also of course separate as before in order to allow the complete moulded sole on the shoe to be withdrawn. An embodiment of the invention which provides such side sealing is illustrated in FIG. 11.

In FIG. 11 support members 80, 81 which carry the welt plates 82, 83 are not hinged to the sole mould member 74 but are carried thereon by pairs of parallel links 84, 85, 86, 87 (one pair at each end of each supporting member). The support members 80, 81 with the attached welt plates 82, 83 thus move both horizontally and with an upward component of direction away from the fully closed position shown, and in the reverse movement the two support members carrying the two side welt plates can thus close sideways on to a last I to complete a sole mould cavity.

The operation of these support members is preferably interconnected with the movement of the last itself so that additional operating rams and guides are eliminated. For this purpose, in a moulding machine of the type shown in FIG. 1, a cam bracket 88 is attached to the outer edge of each of the support members 80, 8i and arranged to be engaged by a profiled cam member 89 rigidly attached to each of the vertical columns 6 carrying the last assembly L. As the columns 6 move downwards these profiled cam members 89 engage the cam brackets 88 and urge the parallel motion support members 80, BI inwards into their closed positions, as shown.

The arrangement is such that the profiled earns 89 do not move the parallel motion support plates 80, 81 into their inner positions until after the last i itself has moved downwards beyond the point where the widest part of the last has cleared the final position of the welt plates 82, 83. The hydraulic ram 9 actuating the columns 6 is associated with an automatic controller or stop which halts the ram when the last is at the required height above the sole mould member 74; if the last,

or the shoe upper on the last, should descend too far and contact the wall of the sole mould member, of course it might form a seal and prevent the liquid moulding material from entering the cavity around the flanks of the shoe and upper on the last. in the final stages of this downward movement of the last assembly L the profiled earns 89 move the parallel motion support plates 80, 81 inwards to close the welt plates 82, 83 against the shoe upper on the last 1.

The parallel motion links 84, 85, 86, 87 are preferably spring urged to the open position so that after moulding the sequence is reversed automatically. As shown in FIG. 11, the spring pressure may be applied through a pair of generally triangular plate members 90, 91 pivoted at 92, 93 respectively on the machine and carrying rollers 94, 95 contacting the lower links 85, 87. A pair of tension springs 96, 97 are attached at one end to the lower ends of the plate members 90, 91 and at their other ends (not shown) to the machine frame, so that the springs tend to turn the plate members and thereby raise the inner ends of the links 85, 87 and hence retract the support members 80, 81 and welt plates 82, 83.

We claim:

I. A mold assembly for forming footwear with molded soles, comprising a sole mold defining a sole cavity, said sole mold including a base and fixed sides providing internal surfaces corresponding to the bottom and sides of a sole, a plurality of movable welt plates pivotally mounted on pivot axes extending parallel with the length of said sole mold and spaced laterally on opposite sides thereof, said welt plates being pivotable about their pivot axes through vertical arcs between a closed position in which said welt plates engage the edge surfaces of said sole mold surrounding said cavity and define the welt surface of the molded sole, and an open position in which said welt plates pivot away from each other and from said sole mold and permit the molded sole to be withdrawn from the mold, and biassing means tending to urge said welt plates towards said closed position, whereby said welt plates are automatically returned towards the closed position before the commencement of each molding operation.

2. A mold assembly according to claim 1, wherein said welt plates are returned to the closed position by gravity.

3. A mold assembly according to claim 1, wherein said sole mold is disposed with said mold cavity opening upwards, and

said welt plates are returned to the closed position under their own weight.

4. A mold assembly according to claim 1, wherein said sole mold is disposed with said mold cavity opening downwards, and including balance weights attached to said welt plates, acting to return said plates to the closed position.

5. A mold assembly according to claim 1, including spring means urging said welt plates to the closed position.

6. A mold assembly according to claim I, wherein said pivot axes are positioned below the level of the welt surface of each welt plate.

7. A mold assembly for forming footwear with molded soles, comprising a sole mold having a base surface and a continuous fixed upstanding wall extending around the periphery of said base surface and substantially perpendicular thereto to define fixed base and side walls of a mold cavity, the upper surfaces of said surrounding wall being non-planar, and shaped to conform to the curvature of the molded sole, a pair of pivotal support members disposed adjacent the outside of said upstanding wall, said support members being respectively secured to said sole mold on a pair of horizontal pivot axes which extend parallel with the length of said sole mold and which are spaced laterally on opposite sides of said sole mold, each support member having a non-planar shaped top surface which in one position of said support member lies flush with the top surface of the adjacent portion of said upstanding wall, a plurality of movable welt plates attached to said top surfaces of said support members, said support members and attached welt plates being movable through vertical arcs about said pivot axes between a closed position in which said welt plates engage and overlie the top surface of said upstanding wall and define the welt surface of the molded sole and an open position in wh|ch said welt plates permit the molded sole to be removed from the mold, and biassing means urging said support members and welt plates towards the closed position to return said welt plates automatically to the closed position before the commencement of each molding operation.

8. A mold assembly according to claim 7, in which said support members engage the outer surface of said surrounding side wall when said welt plates are in their closed position, thereby supporting said side wall against outward movement. 

1. A mold assembly for forming footwear with molded soLes, comprising a sole mold defining a sole cavity, said sole mold including a base and fixed sides providing internal surfaces corresponding to the bottom and sides of a sole, a plurality of movable welt plates pivotally mounted on pivot axes extending parallel with the length of said sole mold and spaced laterally on opposite sides thereof, said welt plates being pivotable about their pivot axes through vertical arcs between a closed position in which said welt plates engage the edge surfaces of said sole mold surrounding said cavity and define the welt surface of the molded sole, and an open position in which said welt plates pivot away from each other and from said sole mold and permit the molded sole to be withdrawn from the mold, and biassing means tending to urge said welt plates towards said closed position, whereby said welt plates are automatically returned towards the closed position before the commencement of each molding operation.
 2. A mold assembly according to claim 1, wherein said welt plates are returned to the closed position by gravity.
 3. A mold assembly according to claim 1, wherein said sole mold is disposed with said mold cavity opening upwards, and said welt plates are returned to the closed position under their own weight.
 4. A mold assembly according to claim 1, wherein said sole mold is disposed with said mold cavity opening downwards, and including balance weights attached to said welt plates, acting to return said plates to the closed position.
 5. A mold assembly according to claim 1, including spring means urging said welt plates to the closed position.
 6. A mold assembly according to claim 1, wherein said pivot axes are positioned below the level of the welt surface of each welt plate.
 7. A mold assembly for forming footwear with molded soles, comprising a sole mold having a base surface and a continuous fixed upstanding wall extending around the periphery of said base surface and substantially perpendicular thereto to define fixed base and side walls of a mold cavity, the upper surfaces of said surrounding wall being non-planar, and shaped to conform to the curvature of the molded sole, a pair of pivotal support members disposed adjacent the outside of said upstanding wall, said support members being respectively secured to said sole mold on a pair of horizontal pivot axes which extend parallel with the length of said sole mold and which are spaced laterally on opposite sides of said sole mold, each support member having a non-planar shaped top surface which in one position of said support member lies flush with the top surface of the adjacent portion of said upstanding wall, a plurality of movable welt plates attached to said top surfaces of said support members, said support members and attached welt plates being movable through vertical arcs about said pivot axes between a closed position in which said welt plates engage and overlie the top surface of said upstanding wall and define the welt surface of the molded sole and an open position in which said welt plates permit the molded sole to be removed from the mold, and biassing means urging said support members and welt plates towards the closed position to return said welt plates automatically to the closed position before the commencement of each molding operation.
 8. A mold assembly according to claim 7, in which said support members engage the outer surface of said surrounding side wall when said welt plates are in their closed position, thereby supporting said side wall against outward movement. 